Add small test program for stb_truetype
This commit is contained in:
Francesco Abbate
parent
4a8df09829
commit
20626ab911
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@ -14,3 +14,4 @@ lite_include = include_directories('src')
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install_subdir('data', install_dir : 'bin')
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subdir('src')
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subdir('tests')
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@ -0,0 +1,18 @@
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lite_sources = [
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'api/api.c',
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'api/renderer.c',
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'api/renderer_font.c',
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'api/system.c',
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'renderer.c',
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'agg_font_freetype.cpp',
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'font_render_capi.cpp',
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'rencache.c',
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'main.c',
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]
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executable('stb-font-render-test',
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'stb_font_render_test.c',
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include_directories: lite_include,
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dependencies: [sdl_dep, stb_truetype_dep, libm, libdl],
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install: false,
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)
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@ -0,0 +1,156 @@
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#include <stdio.h>
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#include <stdlib.h>
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#include <assert.h>
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#include "SDL_surface.h"
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#include "stb_truetype.h"
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#define MAX_GLYPHSET 256
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typedef struct { uint8_t b, g, r, a; } RenColor;
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typedef struct { int x, y, width, height; } RenRect;
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struct RenImage {
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RenColor *pixels;
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int width, height;
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};
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typedef struct RenImage RenImage;
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typedef struct {
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RenImage *image;
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stbtt_bakedchar glyphs[256];
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} GlyphSet;
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struct RenFont {
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void *data;
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stbtt_fontinfo stbfont;
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GlyphSet *sets[MAX_GLYPHSET];
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float size;
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int height;
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};
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typedef struct RenFont RenFont;
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static void* check_alloc(void *ptr) {
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if (!ptr) {
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fprintf(stderr, "Fatal error: memory allocation failed\n");
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exit(EXIT_FAILURE);
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}
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return ptr;
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}
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RenImage* ren_new_image(int width, int height) {
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assert(width > 0 && height > 0);
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RenImage *image = malloc(sizeof(RenImage) + width * height * sizeof(RenColor));
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check_alloc(image);
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image->pixels = (void*) (image + 1);
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image->width = width;
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image->height = height;
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return image;
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}
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void ren_free_image(RenImage *image) {
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free(image);
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}
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RenFont* ren_load_font(const char *filename, float size) {
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RenFont *font = NULL;
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FILE *fp = NULL;
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/* init font */
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font = check_alloc(calloc(1, sizeof(RenFont)));
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font->size = size;
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/* load font into buffer */
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fp = fopen(filename, "rb");
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if (!fp) { return NULL; }
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/* get size */
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fseek(fp, 0, SEEK_END); int buf_size = ftell(fp); fseek(fp, 0, SEEK_SET);
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/* load */
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font->data = check_alloc(malloc(buf_size));
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int _ = fread(font->data, 1, buf_size, fp); (void) _;
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fclose(fp);
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fp = NULL;
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/* init stbfont */
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int ok = stbtt_InitFont(&font->stbfont, font->data, 0);
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if (!ok) { goto fail; }
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/* get height and scale */
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int ascent, descent, linegap;
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fprintf(stderr, "Requesting font size: %g\n", size);
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stbtt_GetFontVMetrics(&font->stbfont, &ascent, &descent, &linegap);
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float scale = stbtt_ScaleForMappingEmToPixels(&font->stbfont, size);
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fprintf(stderr, "Font metrics ascent: %d descent: %d, linegap: %d scale: %g\n", ascent, descent, linegap, scale);
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font->height = (ascent - descent + linegap) * scale + 0.5;
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fprintf(stderr, "Font height: %d\n", font->height);
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return font;
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fail:
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if (fp) { fclose(fp); }
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if (font) { free(font->data); }
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free(font);
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return NULL;
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}
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static GlyphSet* load_glyphset(RenFont *font, int idx) {
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GlyphSet *set = check_alloc(calloc(1, sizeof(GlyphSet)));
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/* init image */
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int width = 128;
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int height = 128;
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retry:
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set->image = ren_new_image(width, height);
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/* load glyphs */
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float s =
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stbtt_ScaleForMappingEmToPixels(&font->stbfont, 1) /
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stbtt_ScaleForPixelHeight(&font->stbfont, 1);
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int res = stbtt_BakeFontBitmap(
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font->data, 0, font->size * s, (void*) set->image->pixels,
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width, height, idx * 256, 256, set->glyphs);
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/* retry with a larger image buffer if the buffer wasn't large enough */
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if (res < 0) {
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width *= 2;
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height *= 2;
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ren_free_image(set->image);
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goto retry;
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}
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/* adjust glyph yoffsets and xadvance */
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int ascent, descent, linegap;
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stbtt_GetFontVMetrics(&font->stbfont, &ascent, &descent, &linegap);
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float scale = stbtt_ScaleForMappingEmToPixels(&font->stbfont, font->size);
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int scaled_ascent = ascent * scale + 0.5;
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for (int i = 0; i < 256; i++) {
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set->glyphs[i].yoff += scaled_ascent;
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set->glyphs[i].xadvance = floor(set->glyphs[i].xadvance);
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}
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/* convert 8bit data to 32bit */
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for (int i = width * height - 1; i >= 0; i--) {
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uint8_t n = *((uint8_t*) set->image->pixels + i);
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set->image->pixels[i] = (RenColor) { .r = 255, .g = 255, .b = 255, .a = n };
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}
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return set;
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}
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int main(int argc, char *argv[]) {
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if (argc < 3) {
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fprintf(stderr, "usage: %s <font-filename> <size>\n", argv[0]);
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return 1;
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}
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const char *filename = argv[1];
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const int size = atoi(argv[2]);
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RenFont *font = ren_load_font(filename, size);
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GlyphSet *set = load_glyphset(font, 0);
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SDL_Surface *surface = SDL_CreateRGBSurfaceWithFormatFrom(
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set->image->pixels,
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set->image->width, set->image->height, 32, set->image->width * 4,
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SDL_PIXELFORMAT_RGBA32);
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SDL_SaveBMP(surface, "stb-glyphset.bmp");
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return 0;
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}
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